mainline inclusion
from mainline-5.0-rc1
commit d24e3c98ac11b941669885cc09d88b3b970e9d66
category: bugfix
bugzilla: NA
CVE: NA

-------------------------------------------------
Add a 'lost count' to 'perf top' headers:

  # perf top --stdio
   PerfTop:    3850 irqs/sec  kernel:49.0%  exact: 100.0% lost: 0/0 [4000Hz cycles:ppp],  (all, 8 CPUs)

  # perf top
  Samples: 0  of event 'cycles:ppp', 4000 Hz, Event count (approx.): 0 lost: 0/0

The format is: <current period lost>/<total lost>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/n/tip-zo11rn270gij5jtp8fknpf8u@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NChunmei Xu <xuchunmei@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>